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PubMed1975

HL-A, fertility and natural selection.

The antibodies occasionally produced in gravid females usually cause no adverse effects and the mother may become hyporesponsive. Exceptions may occur in some cases of abortion where frequency of antibodies appears to be unduly high. Sperm antigens in the mouse include T locus alleles as well as H-2 and H-Y. The T locus is involved in differentiation. T locus alleles are expressed on early but not late embryos. A search for similar factors in man is in progress. The antigenic differences between sperm and mother and between foetus and mother may be important in natural selection. It is possible that the union of sperm with ovum is non-random and that the ovum can select "compatible" sperm through recognition of cell surface markers present on sperm. Immunologic differences between mother and foetus may cause local "graft-versus-host" reactions in the placenta. This leads to increased placental size and may be a factor in hybrid vigour as well as a protective device.

Antibody Formation↗
PubMed2001

Pale vacuolated epithelial cells in epididymis of aflatoxin-treated mice.

The responses of the mouse epididymal epithelium to subchronic doses of aflatoxin B1 were investigated in a histological study. Either few and large or small and profuse vacuoles containing an amorphous to dense periodic acid-Schiff-positive material were observed in the epithelium of all the segments of the epididymis. Resin-embedded semi-thin sections and transmission electron microscopy indicated that these vacuoles were intracellular. The cells that contained these vacuoles were quite different in organization and electron density from the cell types already established in the epididymal epithelium and are designated as pale vacuolated epithelial cells. Owing to aflatoxin B1 toxicity, the apical membrane of some of the principal cells, either individually or in groups, disintegrated so that the principal cells released their contents into the lumen of the duct through development of a 'fistula'. Spermatozoa from the ductal lumen entered the principal cell fistula and reached the basal lamina. If extravasation of the spermatozoa via this route occurred, it would bring about an autoimmune response, leading to the formation of spermatic granulomas and the generation of anti-sperm antibodies. Extravasation of spermatozoa seems to be offset by the underlying basal cell, which is presumed to develop into a pale vacuolated epithelial cell to enclose the disintegrating principal cells and the spermatozoa arriving at the principal cell. Thus, the development of pale vacuolated epithelial cells may be a protective device preventing an autoimmune response to sperm antigens in the context of toxicant-induced degeneration of the principal cells of the epididymal epithelium.

Acrylic Resins↗
PubMed2004

Dose responses of years of exposure on lung functions in flour mill workers.

Flour dust is a heterogeneous substance with respiratory sensitizing properties; its long-term exposure may cause acute or chronic respiratory diseases. Therefore, the aim was to investigate the dose response effects of flour dust on lung function. An additional objective was to minimize the potential health risks in flour mill workers by providing them with information about the hazards of flour dust. Pulmonary function was studied in forty-six male flour mill workers who worked without the benefit of flour dust control ventilation or respiratory protective devices and a similar number of male control subjects. All participants were non-smokers and were matched for age, height, weight and socio-economic status. Pulmonary function tests were performed by using an electronic Spirometer and results were compared by a paired t-test. The present study results showed a significant decrease in the mean values of FVC, FEV(1), PEF and MVV and this impairment was increased with duration of exposure in the flour mills. This group of flour mill workers had occupationally related pulmonary function impairment and stratification of results showed a dose response of years of exposure in flour mills on lung function.

Adolescent↗
PubMed2005

Distal embolus protection with an intra-aortic filter during stent-graft repair of a severely atherosclerotic thoracic aortic aneurysm.

PURPOSE: To assess the technical feasibility and efficacy of distal embolus protection with an intra-aortic filter during stent-graft repair in a patient diagnosed with a shaggy aorta. TECHNIQUE: In a 75-year-old man with a severely atherosclerotic thoracic aortic aneurysm, stent-graft repair was combined with transposition of the arch branches to the ascending aorta under thoracotomy. A filtration-type embolus protection device with a nitinol basket and polyester fabric was introduced through a 12-F sheath and opened in the supraceliac aorta during the stent-graft procedure; it was safely pulled back into the sheath after the stent-grafts were implanted. The stent-graft repair was successful, and abundant atheromatous debris was captured in the filter. Neither procedure-related embolic events nor neurological deficits were observed. CONCLUSIONS: Use of the intra-aortic filter device to prevent distal embolism during thoracic stent-graft repairs may be feasible and efficacious in severely atherosclerotic patients.

Aged↗
PubMed2005

Renovascular hypertension.

Renal artery disease is the most common cause of potentially curable secondary hypertension, with atherosclerosis as the major cause of renal artery stenosis. Fibromuscular dysplasia is a less common cause of renal artery stenosis and is most frequently observed in premenopausal women. Renal artery stenosis is likely to be underappreciated and is more common in patients with other vascular disease (e.g., coronary or peripheral arterial disease). The diagnosis of renal artery stenosis requires a high clinical index of suspicion as well as an appropriate imaging strategy, with currently effective diagnostic modalities including magnetic resonance imaging, computed tomography and renal artery duplex ultrasonography. The current treatment of choice for atherosclerotic renal artery stenosis is balloon angioplasty and secondary stenting, whereas angioplasty alone is the treatment for renal artery stenosis secondary to fibromuscular dysplasia. Expected outcomes following revascularization include improved blood pressure control and possibly renal preservation. Ongoing studies will hopefully identify patient characteristics that will achieve the most benefit from percutaneous revascularization as well as the impact of percutaneous revascularization with drug-eluting stents and embolic protection devices.

Humans↗
PubMed2001

Intracoronary brachytherapy in the treatment of in-stent restenosis. Initial experience in Brazil.

Intracoronary brachytherapy using beta or gamma radiation is currently the most efficient type of therapy for preventing the recurrence of coronary in-stent restenosis. Its implementation depends on the interaction among interventionists, radiotherapists, and physicists to assure the safety and quality of the method. The authors report the pioneering experience in Brazil of the treatment of 2 patients with coronary in-stent restenosis, in whom beta radiation was used as part of the international multicenter randomized PREVENT study (Proliferation REduction with Vascular ENergy Trial). The procedures were performed rapidly and did not require significant modifications in the traditional techniques used for conventional angioplasty. Alteration in the radiological protection devices of the hemodynamic laboratory were also not required, showing that intracoronary brachytherapy using beta radiation can be incorporated into the interventional tools of cardiology in our environment.

Aged↗
PubMed2005

The thrombus laden coronary artery--forget the fancy stuff, just aspirate it!

"No-reflow" is an important complication of percutaneous coronary intervention (PCI) in the setting of acute myocardial infarction and is associated with worse outcomes. Visible thrombus on the angiogram is a significant risk factor for "no-reflow". A variety of strategies have been employed to prevent this phenomenon including intracoronary vasodilators and distal protection systems. Randomized trials have not revealed any superiority of distal protection devices despite the theoretical rationale to their use. We describe a case of a thrombus-laden right coronary artery in which PCI would have likely resulted in significant "no-reflow". A simple aspiration catheter was used to significantly reduce the thrombus burden. Subsequent stenting was performed with no adverse events. This case illustrates the benefit of a less fancy approach to the thrombus-filled coronary artery - just aspirate it! Randomized trials are needed to test the role of simple aspiration prior to stenting in thrombus-laden coronary arteries.

Angioplasty, Balloon, Coronary↗
PubMed2006

Effects of thrombus suction therapy on myocardial blood flow disorders in males with acute inferior myocardial infarction.

Several studies have reported that the use of a distal protection device decreases the incidence of slow-flow and/or no-reflow in patients with myocardial infarctions. In the present study, we investigated the influence of a RESCUE/Thrombuster system and a PercuSurge GuardWire catheter on coronary microcirculation disorders in patients with acute myocardial infarction using the natriuretic polypeptide (ANP), the brain natriuretic peptide (BNP), and (99m)Tc-tetrofosmin myocardial scintigraphy (TF). The group consisted of a 77 patients with initial inferior myocardial infarction who had undergone emergency coronary angioplasty. The patients were randomly divided into: Group D (n=28), in which a direct stent alone was inserted, Group R/T (n=25), in which a stent was inserted after RESCUE system or a Thrombuster system was performed, and Group P (n=24), in which a stent was inserted after thrombus suction using a PercuSurge GuardWire catheter. Patients with coronary slow-flow/no-reflow were 3, 2 and 0 cases in Group D, Group R / T and Group P, respectively. In the present study, patients with good-reflow were enrolled in order to investigate the coronary microcirculation disorder in patients with visually similar coronary blood flow obtained in coronary angiography after percutaneous coronary reperfusion therapy. TF myocardial scintigraphy was performed 10+/-3 days after admission. Bull's eye images were divided into 8 sections, and each section was evaluated in 4 grades. The grade of each segment was regarded as the defect score. The results were compared with the database prepared based on bull's eye maps from 50 healthy adults in our hospital, and count areas of -2 x SD (standard deviation) or less were calculated as the extent score (%), reflecting the area in which myocardial blood flow was decreased. The extent and severity scores in Groups P and R/T were significantly lower than those in Group D. Coronary angiography at the chronic stage (6 months after surgery) showed the patency of the responsible vascular lesion in all patients. However, the ANP, BNP, cardiac index, and pulmonary capillary wedge pressure (PCWP) were significantly improved in Groups R/T and P, compared to Group D (p<0.01). These results suggest that the use of a RESCUE/Thrombuster system and a PercuSurge GuardWire catheter system in patients with acute inferior wall infarction improves coronary microcirculation disorders and acute- to chronic-phase cardiac function.

Aged↗
PubMedDate not supplied

Mouth guards for the prevention of injuries in contact sports.

There has been a significant increase in the number of individuals participating in contact sports. As a result, every effort must be made to provide the athletes with protection against mouth injuries. In this review the use, construction and benefits of mouthguards in all sports has been described. There is unanimous opinion attesting to the benefits of such protective devices and in those sports where the athlete is required to wear a mouth guard, a dramatic decrease in the number and severity of injuries has been reported. Custom-fitted mouth guards should be used in many sports that do not already have a compulsory rule requiring their use. Physicians, dentists, trainers and coaches need to be educated on the data supporting the benefits described. Studies on performance enhancement as a result of mandibular orthopaedic repositioning appliances have also been reviewed. Long term studies are required to assess the claims of ergogenic enhancement utilising proper study design. Current evidence exists relating to the effects of psychological phenomena on athletic performance, and it is believed the placebo effect contributes to the findings of performance improvement.

Athletic Injuries↗
PubMed2004

Adjunctive therapy for percutaneous revascularization in acute myocardial infarction.

Primary PCI is an effective reperfusion strategy for acute MI patients, which has evolved significantly in the last decade. While many adjunctive therapies have contributed to its success, substantial obstacles remain before optimal reperfusion can be achieved. Anti-platelet therapy with aspirin, clopidogrel and GP IIb/IIIa inhibitors reduces early ischemic complications, improves microvascular function and, potentially, affects the inflammatory response to ischemic injury. Current anti-thrombin therapy with UFH can be improved with LMWH, and, possibly with direct thrombin inhibitors. A number of important aspects of this strategy, though, need still to be elucidated. We need to optimize microvascular protection before and during PCI in order to capitalize on the myocardial sparing effects of reperfusion therapy. This will be probably achieved with a combination of pharmacological interventions and mechanical emboli protection devices. Improved and more targeted anti-inflammatory therapy should decrease the effects of neutrophil-related reperfusion injury, while a variety of metabolic interventions might preserve myocardial function during ischemia and after reperfusion.

Angioplasty, Balloon, Coronary↗
PubMed2001

Percutaneous coronary intervention: current perspective.

More than 20 years have passed since percutaneous transluminal coronary angioplasty (PTCA) was introduced for the treatment of coronary artery disease. During the first decade, PTCA outcome had improved significantly. However, acute occlusive complications and restenosis remained as significant limitations of the procedure. During the second decade, new procedures, such as stents and atherectomy (directional coronary atherectomy, and Rotablator) had been introduced and had a significant impact on the outcome of percutaneous coronary intervention (PCI). In addition to the improvements in the equipment, the use of glycoprotein IIb/IIIa inhibitors to prevent platelet aggregation has reduced procedure-related complications. PCI continues to evolve with new developments such as distal protection devices to prevent distal embolism, brachytherapy and drug-eluting stents to prevent restenosis. These new technologies may play a significant role in expanding the applications of PCI in the future.

Angioplasty, Balloon, Coronary↗
PubMed2006

Exposure to organic solvents among handicraft car painters: A pilot study in Italy.

Car repair painters usually experience long-term exposure to many different solvents. In Italy, the greater part of car painting shops are "handicraft", i.e. 2-5 workers and small premises. Usually workers do not have specific duties, but everyone takes part in all different operations. Moreover, working time is not standardized but varies according to the workload, working methods tend to be traditional, and compliance to individual protection devices is poor. We have hence assessed, on a sample of 8 italian handicraft car painting shops, the exposure levels to solvents, implementing three classic exposure monitoring methods: environmental sampling with charcoal tubes, personal sampling with diffusive charcoal samplers, and urinary determination of unmetabolised solvents. A simple regression analysis was performed to evaluate relationships between the three series of data. The solvents analysed were toluene, ethylbenzene, 1, 2-dichloropropane, n-butylacetate, n-amylacetate, xylene isomers, ethylacetate, and benzene. Benzene was included due to several factors, among others its presence (1% v/v) in the italian unleaded gasoline. Benzene was found in all shops, at levels around or higher than the 8-h time-weighted average limit (8-h TLV-TWA). Other solvents were found in the different shops at various levels, 10(-2) - 10(-1) times the 8-h TLV-TWA. Air concentrations of toluene, n-butylacetate, xylenes, and benzene were positively correlated with urinary levels of the parent compounds, while a negative correlation was found for ethylbenzene. The health implications of workers' exposure level was briefly discussed.

Automobiles↗
PubMed2006

A study on compliance to hearing conservation programme among industries in Negeri Sembilan, Malaysia.

Noise is one of the hazards faced by workers. A cross-sectional study was conducted among industries in Negeri Sembilan with the objective to assess their compliance to Hearing Conservation Programme (HCP). The other objectives of this study were to determine the factors influencing it and to show the industries' compliance to each element of the programme. It was also to identify the association between compliance to HCP and the prevalence of hearing impairment and standard threshold shift. Data for this study were collected using questionnaires sent by mail and also the results of the latest audiometric tests. A total of 167 industries were analysed for this study. It was found that 41.3% of these industries fully complied to the programme. It was also found that the industries preferred to provide hearing protection device (92.8%) and least complied to noise control (61.1%). There were significant associations (p<0.05) between compliance and number of employees, status of ownership and the presence of officer in charge of hearing conservation programme. Having at least 150 employees actually raised the compliance to HCP in two folds (beta = 0.717, OR = 2.048, C.I 95% = 1.063 to 3.944). The prevalences of hearing impairment and standard threshold shift were 23.9% and 5.2% respectively. There was no significant association between the prevalence for hearing impairment and compliance to HCP. The prevalence for standard threshold shift was inversely related to compliance. This study showed that compliance percentage need to be improved as an effort to prevent the hearing problems among workers exposed to noise.

Adult↗
PubMedDate not supplied

Method for long-term cerebrospinal fluid collection in the conscious dog.

In medical research there is often a need for cerebrospinal fluid (CSF) collection from conscious animals. A number of models have been published, but long-term use is often limited by factors such as damage to implant or loss of patency. When part of an implant is exteriorized, group housing is often not possible; even when singly housed, the instrumented animals might have to be fitted with protective devices such as collars, vests, or helmets. Over the last 10 years we have, through the use of this technique, managed to perform repeated CSF collections in 12 beagles. Time of implant duration has ranged from 2.3 to 6.8 years. The method uses two permanent stainless steel guide cannulas screwed into the parietal bone, positioned above but not penetrating the lateral ventricles of the brain. At the time of collection, one of the subcutaneous stainless steel cannulas is used to serve as a guide for a 20-gauge collection needle. The collection is performed under local analgesia and with minimal discomfort to the dog. With its long-term use, we feel that this model is very useful and of high ethical and welfare standards due to the virtual lack of postoperative complications, maintenance requirements, and housing restrictions.

Animals↗
PubMed2000

Gene therapy for hemophilia.

Hemophilia A and B are X-linked genetic disorders caused by deficiency of the coagulation factors VIII and IX, respectively. Because of the health hazards and costs of current product replacement therapy, much effort is devoted to the development of gene therapy for these disorders. Approaches to gene therapy for the hemophilias include: ex vivo gene therapy in which cells from the intended recipients are explanted, genetically modified to secrete Factor VIII or IX, and reimplanted into the donor; in vivo gene therapy in which Factor VIII or IX encoding vectors are directly injected into the recipient; and non-autologous gene therapy in which universal cell lines engineered to secrete Factor VIII or IX are enclosed in immuno-protective devices before implantation into recipients. Research into these approaches is aided by the many murine and canine models available. While problems of achieving high and sustained levels of factor delivery, and issues related to efficacy, safety and cost are still to be resolved, progress in gene therapy for the hemophilias has been encouraging and is likely to reach human clinical trial in the foreseeable future.

Animals↗
PubMed1998

Complications of carotid angioplasty and stenting.

The authors report the complications that occurred in their experience with performing recanalization procedures in the internal carotid artery and present their treatment strategies. The complications can be classified into those that were periprocedural and those that were postprocedural. The former include complications related to the vascular-approach access site of and those associated with the dilation and stenting procedure. Other complications observed included embolic events, dissection, vascular spasm, bradycardia, inappropriate dilation, occlusion of the external carotid artery, and rare, unusual complications such as the occurrence of iatrogenic cavernous carotid fistula. Postprocedure complications occurred in the hours and days following the procedure in the form of embolic and occlusive events, and hypotension and bradycardia were seen as late complications in the months following the procedure. The authors discuss how such complications occur and provide suggestions on how to avoid them. The role of stent placement and the potential use of protective devices are explored. Overall, adequate use of currently available systems allows for safe application of endovascular treatment techniques that avoid altogether or treat these potential complications. A reduced incidence of complications related to the initial individual learning curve may be obtained with preclinical training, in which use of invitro models should be considered. Surgical standby no longer seems required; however, early posttreatment surveillance in intensive care unit is mandatory to avoid the remaining primary complications.

Journal Article↗
PubMed2005

Toward clinical equipoise: the current case for carotid angioplasty and stent placement.

Recent advances in carotid artery (CA) stent placement procedures have propelled this technology into the forefront of treatment options for both symptomatic and asymptomatic patients with CA stenosis. Until recently, endarterectomy was the only surgical option for patients with CA occlusive disease. For high-risk surgical candidates, periprocedural stroke rates remained unacceptable and were significantly higher than those associated with the natural history of the disease. Advances in stent technology and improvements in antiplatelet and antithrombotic regimens, in conjunction with distal protection devices, have significantly lowered the risk of periprocedural complications for high-risk surgical candidates requiring CA revascularization. In this paper the authors review data gleaned from the important recent CA stent trials and address questions concerning the safety, efficacy, and durability of stent-assisted angioplasty for extracranial CA occlusive disease. Additionally, they review the role of noninvasive imaging modalities for the diagnosis and surveillance of CA disease in these high-risk patients.

Angioplasty↗
PubMed2005

Endovascular management of carotid artery disease after radiation therapy and radical neck dissection.

OBJECT: More patients with head and neck cancers who undergo radical neck dissection and adjuvant radiation are experiencing prolonged survival times. Because of their improved survival, patients are living long enough to suffer the delayed effects of radiation therapy. Radiation-induced carotid artery (CA) stenosis in patients with or without radical neck dissection often requires extensive exposure and vessel reconstruction. The aim of this study was to evaluate the efficacy of endovascular treatment as an alternative therapy for radiation-induced CA stenosis. METHODS: Coinciding with the improved longevity of these patients, CA angioplasty and stent placement has become a definitive treatment strategy for this particularly challenging group of individuals. Long lesions are easily addressed with multiple telescoped stents. The tendency toward early restenosis can now be addressed with cutting balloon angioplasty. A review of the authors' institutional database yielded five patients (four men and one woman) with a history of radiation treatment ipsilateral to their CA stenosis. Three of five patients were symptomatic, and the interval between radiation therapy and endovascular treatment ranged from 1 to 47 years (mean 16.6 years). Four of the five patients were treated using distal embolic protection devices, and all patients underwent balloon dilation after stent placement. CONCLUSIONS: As advancements are made in the technology and techniques for CA angioplasty and stent placement, the safety and durability of treatments in patients with radiation-induced atherosclerotic disease will improve.

Aged↗